In the marine world, the term “tuning” has a somewhat different meaning to what is understood by the same term in the automotive world.
Apart from the small engines used in the common sort of pleasure craft, most marine diesels are fairly large and correspondingly powerful, and represent proportionate financial investment. Perhaps for this reason, the engines are so equipped as to enable the owner to establish, when thought fit, that they are delivering the rated power, as they did when new. Two factors make this possible: each cylinder has its own high-pressure fuel injection pump, and also has a fitting to which may be attached a “peak pressure” gauge, or an “indicator” which traces out a graph of cylinder pressure vs crank angle. When the latter indicates that a certain cylinder is below par, its fuel pump may be adjusted as needed to correct the deficiency. In any case, every cylinder has its own exhaust temperature gauge permanently in place, which can give early warning if all is not well, and that “tuning” may be needed.
(Recent engines with "common-rail" injection systems are somewhat different, but the same principle applies).
I have been wondering what the builders of F1 engines do to ensure that each cylinder is performing with equal efficiency. Compression pressure measurements tell only part of the story, because it is the actual combustion process that determines cylinder output, this in turn depending on flow through the valves, turbulence, timing of both injection and spark, spray pattern and droplet size, and so on. And of course, the dynamometer can only give the sum total power developed, not how that is shared by the cylinders.
On the other hand, when seeking the ultimate power output, it makes sense to ensure that every cylinder performs as intended, instead of varying randomly in response to the dozens of factors that may have an effect. Apart from the few mentioned in the previous paragraph, the airbox flow pattern, tolerances in every part that figures in the gas flow path, surface finishes, lube oil flow quantity and pattern…….
Anyone have any idea of the state of the art in this field?